𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Recent topics concerning the acoustics of fibrous and porous materials

✍ Scribed by Jean-François Allard; Philippe Herzog; Denis Lafarge; Masayuki Tamura

Publisher
Elsevier Science
Year
1993
Tongue
English
Weight
778 KB
Volume
39
Category
Article
ISSN
0003-682X

No coin nor oath required. For personal study only.

✦ Synopsis

Recent developments in the theory for acoustical properties of porous materials with rigid frames introduced two characteristic dimensions related to the high-frequency behaviour of the viscous forces and the thermal exchanges in addition to the classical parameters of porosity, flow resistivity and tortuosity. These characteristic dimensions are used with recent expressions of the effective mass and the compressibifity of the air in porous materials to predict the surface impedance in the high-frequency range. Measurements of the surface impedance performed in a free field are used to evaluate the accuracy of the model. The same model is generalised in the context of the Biot theory to the case of elastic framedmaterials. The effect of the.frame wave on the surface impedance of a layer of fibrous material, and on the transmission through a fibrous material bonded onto a plate is studied with this new model.

📜 SIMILAR VOLUMES

Equipment for measuring the flow-resista
Equipment for measuring the flow-resistance of porous and fibrous materials
✍ D. Huszty; A. Illenyi; Gy. Vass 📂 Article 📅 1972 🏛 Elsevier Science 🌐 English ⚖ 735 KB

We constructed a sh:gle-purpose equipment for the investigation of the flow resistance' of porous and fibrous acoustical materials utilised in sound absorbing devices. The equipment serving for the measurement underlies on the arrangement reported also by Beranek. 5-9 In its appropriate shaping supp

A weighted residual formulation of the a
A weighted residual formulation of the acoustic wave propagation through a flexible porous material and a comparison with a limp material model
✍ P. Göransson 📂 Article 📅 1995 🏛 Elsevier Science 🌐 English ⚖ 603 KB

A weak formulation of the coupled acoustic-elastic wave propagation through a flexible porous material is presented for a one-dimensional case. The discretized form of the equations governing the wave propagation through the porous material is derived from a weighted residual statement, involving ex